Key Insights
International scientists in the US face a worsening visa bottleneck, marked by prolonged administrative processing, new fee and lottery rules, tighter status limits, and broader enforcement uncertainty.
The US research system depends heavily on international talent, especially in chemistry and other science, technology, engineering, and mathematics fields.
Researchers, universities, and immigration experts are responding with workarounds such as legal maneuvering and overseas placements, while advocacy groups warn that trust in the US as a destination for scientific talent may take years to rebuild even if policies change.
Kumar’s fascination with chemistry began on a flickering tube television in India. Watching Peter Parker mix solutions to invent web fluid, he saw a roadmap: if a student could imagine a formula to carry him across skyscrapers, chemistry must hold infinite possibilities.
Kumar, who requested that only his middle name be used, arrived in the US for a postdoctoral fellowship in 2023 on a J-1 exchange visitor visa, the category commonly used by postdoctoral researchers. As his taxi rolled through Queens in New York City, he saw the very same red-brick buildings his childhood hero once swung across.
“The very next day, I called my mother and told her that since Spidey is by my side, I’ll definitely find an eco-friendly way to break down PFAS,” he recalls, referring to per- and polyfluoroalkyl substances. “I’m sure she didn’t understand much, but she knew I was happy.”
The dream held for 2 years. In March 2025, Kumar returned to India to care for his ailing sister. The trip was meant to be a brief pause, but at the US embassy, his academic career hit an invisible wall. The renewal of his 2-year research visa was diverted into “extended administrative processing,” a bureaucratic black box involving expanded security screening and background checks.
Kumar has not been able to return to the US since. The environmental chemistry project he pioneered moves forward with him only peripherally involved.
US visa rules tighten for international researchers
Kumar’s visa predicament is not new for international researchers in the US. But, although federal data for 2025 are not yet available, individual analyses by third parties have reported a severe worsening of the situation in the past year.
“In my 37 years . . . I have never seen such a perfect storm.”
Fanta Aw, executive director and CEO , NAFSA: Association of International Educators
According to US Department of State data analyzed by the Chronicle of Higher Education, the issuance of F-1 student visas, used by international students pursuing degrees such as PhDs in the US, fell 36% from the previous year during the critical summer months of May–August 2025. Data from Shorelight, an educational organization that assists international students in studying in the US, show that refusal rates for F-1 applications reached a decade high of 35%, and issuance of J-1 visas also declined, dropping 13% in May 2025 alone. India, the largest source of international science, technology, engineering, and mathematics (STEM) talent in the US, saw some of the steepest drops.
“In my 37 years of being in this field, I have never seen such a perfect storm,” says Fanta Aw, executive director and CEO of NAFSA: Association of International Educators, describing a climate of visa restrictions, funding freezes, and policy volatility that has “fueled distrust and tremendous fear” in the decades-old US system for recruiting, hosting, and supporting international researchers.
The clearest symptom, says Dan Maranci, an immigration lawyer at WR Immigration, is “unpredictability.”
“While the [immigration] statutes remain largely unchanged, the adjudication machine has shifted,” he says. Even as applicants and legal firms increasingly use artificial intelligence tools to translate dense scientific research and technical documentation into formats accessible to nonexpert immigration officers reviewing visa applications, the government has applied a “magnifying glass across the board, ratcheting up the standard for previously routine [visa] approvals.”
F-1: Student visa for undergraduate, master’s, and PhD programs
J-1: Exchange visa commonly used by researchers and postdoctoral scholars
Challenges
Expanded social media and background checks at US embassies are slowing visa processing and disrupting visa renewals and reentry, delaying researchers’ return to US labs and interrupting ongoing work.
A proposed rule to replace the duration-of-status system with fixed visa end dates would require students and researchers to seek government approval to extend their stay, reducing flexibility to complete long or unpredictable academic programs.
Temporary work permission after completing a degree (F-1 visa holders only)
Allows up to 12 months of work in the field of study
Person can be unemployed for up to 90 days total during this period
Challenges
Replacing the duration-of-status system would introduce uncertainty about whether graduates can remain in the US and pursue OPT after completing their degree.
New H-1B visa requirements, described below, are making employers reluctant to hire OPT candidates due to the risk that the candidates will not be able to obtain an H-1B and stay long term.
Extra work time for graduates in science and technology fields
Adds 24 additional months of work authorization (a total of up to 3 years on OPT)
Challenges
An ongoing federal review of both the standard OPT and science, technology, engineering, and mathematics (STEM) OPT rules is creating uncertainty in the pathway that allowed more than 95,000 international graduates in 2024 to transition into the US workforce.
Employer-sponsored work visa for longer-term employment
Requires a job offer and employer sponsorship
Typically used to continue working in the US after OPT ends
Challenges
A wage-weighted lottery for determining which H-1B applications are reviewed gives higher-paid applicants more chances of selection, reducing access for early-career researchers and recent graduates.
A $100,000 fee on H-1B applications for candidates outside the US raises sponsorship costs and discourages employers from hiring international researchers.
Innovation Siphon
New H-1B lottery and fee rules for international hires are pushing international researchers into temporary academic positions to stay legal, reducing the supply of talent in US research and development.
H-1B work visa for universities and nonprofit research intuitions
Not subject to the H-1B lottery
Common for jobs in academia, teaching hospitals, and research institutes
Challenges
State policies in Texas and Florida that are blocking public universities from filing new H-1B petitions are cutting off a key pathway for international researchers to take academic jobs in the US.
Yang Ku/C&EN/Shutterstock, scroll animation by Kay Youn
New data added into visa adjudication systems have amplified the risk of erroneous or automated visa revocations, Maranci says. In the past year, as part of a broader shift in enforcement, criminal databases have been fed more directly into visa adjudication systems, triggering “sudden revocations without human analysis.” He explains that the automated process has swept up innocent victims, including one researcher whose visa was revoked simply because their name appeared in a report as an accident victim, not a perpetrator.
Financial barriers for visa-applying researchers have also risen.
A 2025 proclamation by President Donald J. Trump imposed a $100,000 fee on international scientists who want to apply for H-1B visas, which typically allow foreign PhD graduates to transition from training status to temporary employment in the US. H-1B visas are also used more broadly to hire foreign professionals in the US.
Gil Guerra, an immigration policy expert at the Niskanen Center, a US think tank, calls the cost “effectively prohibitive” for academic institutions that rely on H-1B visas to employ some foreign researchers. Sonali Majumdar, author of Thriving as an International Scientist, says the fee creates a major obstacle to recruiting researchers from outside the US. In a resource-constrained environment, she says, employers have become “very risk averse,” often avoiding international candidates if the visa pathway requires any “creative thinking.”
H-1B prospects for postdocs are further complicated by new rules governing which H-1B petitions will be processed.
A rule that went into effect in February creates a weighted lottery system for getting an H-1B application reviewed, in which higher salaries translate into more lottery entries. “A postdoc at $55,000 gets one entry,” Guerra says. “An industry software engineer at $180,000 gets four.”
Mary E. Walsh, an immigration attorney at Iandoli, Desai, & Cronin, believes an upcoming shift may prove even more consequential. In 2026, the government plans to eliminate the duration-of-status rule, which historically allowed F-1 and J-1 visa holders to remain in the US as long as their academic programs required.
Instead, these visas would have fixed expiration dates, which will transfer control of the academic timeline from universities to immigration authorities.
“It forces scientists to prove the necessity of their stay to a bureaucrat rather than a university, turning research timing into a discretionary government decision,” Walsh says.
For chemists like Kumar, the infinite possibilities of the lab are increasingly dictated by a system where, as Maranci puts it, every legal strategy now carries a permanent asterisk: “This could change next week.”
Visa stress takes a toll on researchers’ mental health
The uncertainty has moved beyond professional inconvenience. For the international scientists dealing with the US immigration system, the stress is becoming clinical.
A 2025 study of over 700 international postdoctoral researchers at Harvard Medical School and its affiliated institutions reveals that 75% of respondents experienced mental-health challenges—including anxiety and panic attacks—directly linked to visa stress. The strain was severe enough that 29% were forced to take time off work, while 11% required prescription medication to manage it.
And the numbers might be only the tip of the iceberg.
“International researchers often hesitate to seek psychological support, both because of cultural norms around disclosing personal struggles and because the current climate has created tremendous fear,” Aw says.
Nevertheless, “our international researchers are incredibly resilient,” she says. “Many compartmentalize what they are experiencing personally while continuing to focus on their work.”
Majumdar believes that these pressures are accented by the short-term nature of academic careers. Because international postdocs often rely on visas tied to specific, temporary appointments, they have little margin for the bureaucratic delays that are becoming standard.
“We do anticipate there will be shrinking of the research that is done, at least in the short term,” Majumdar says, leaving some scholars to “reconsider whether to remain in academic research altogether.”
A climate of fear deters global research talent
Yet even if researchers push forward with their experiments despite the personal toll of rising visa challenges, they must still contend with the climate of fear, fueled by federal agencies’ show of force, that is hollowing out many US labs.
“You can call our concerns misplaced, but my roommate and I are scared to go to the supermarket to get even the most basic necessities.”
Mohammad, biochemist
Mohammad, a biochemist from Bangladesh who is currently in an integrated PhD program, describes living in a state of self-imposed lockdown after raids by US Immigration and Customs Enforcement on his campus and in his neighborhood. His family and his roommate’s family, both back home, now urge them not to leave their apartment. Mohammad also requested that only his middle name be used.
“You can call our concerns misplaced, but my roommate and I are scared to go to the supermarket to get even the most basic necessities,” he says.
This shift in atmosphere is severing the recruitment chain at its source.
Imran Khan, an adviser at Humstudy, an Indian overseas education consultancy, says current students are warning aspirants in their home countries to look elsewhere, triggering a wave of canceled plans to study in the US.
“Not that the most sought-after universities are recruiting international students either. Funding cuts have seen to that,” Khan says.
“The United States used to be the sure-fire destination for international researchers. That assumption is no longer guaranteed.”
Thomas P. Kimbis, executive director and CEO, National Postdoctoral Association
The National Postdoctoral Association (NPA), which includes the highly active International Committee, sees this fear of starting life in the US, instability, and terror of deportation playing out on a broader scale.
“The United States used to be the sure-fire destination for international researchers,” says Thomas P. Kimbis, executive director and CEO of the NPA. “That assumption is no longer guaranteed.”
In prior years, international scholars made up roughly 60% of the association’s postdoc population. Now, the NPA is anticipating a major decline in new international postdocs entering the US, though federal data have yet to capture the trend.
Visa rules limit career mobility for foreign researchers
Even before these recent policy shifts, immigration rules posed considerable challenges to foreign researchers, shaping their career paths and limiting their mobility.
The need for visa sponsorship from potential employers has always been a key challenge, leaving many international graduates with sharply constrained job prospects compared with their US peers.
But the changes to H-1B policies have intensified that constraint several-fold: as visa pathways grow more complex and costly, employers have become increasingly reluctant to hire candidates who require sponsorship.
In addition, nearly half of participants in the Harvard study reported feeling “trapped” in their current roles, often forced to remain in toxic work environments because, across visa categories, resigning gives them only a limited time frame to secure a new job and visa sponsor before losing legal status.
The current immigration system is further impacting where foreign researchers who remain in the US end up working.
Walsh notes that while the private sector is governed by the high-stakes H-1B lottery, where high fees and a bias toward industry salaries dictate which applications are selected under the annual cap, universities can sponsor visas outside this cap. This cap-exempt status for researchers within the US provides a safety net that inadvertently “acts as an innovation funnel, pushing talent away from industry and back into academia,” she says.
Though it may offer short-term stability for graduate students and postdocs, this route locks many into academic tracks they might not otherwise choose, largely because their positions are structurally fragile.
Majumdar notes that international PhD students are far less likely than their US peers to hold independent fellowships, with most instead tied to faculty grants that also anchor their visa status. This means disruptions in funding or supervision can quickly become immigration crises. This dynamic extends to postdocs, who occupy an equally precarious institutional middle ground, she says.
Without permanent employment status, many postdocs cycle through temporary work authorizations with little path to stability. Recent policy shifts have intensified this precarity, as stricter visa scrutiny and an expanded vetting system both restrict movement into industry roles and increase the risk of immigration-status disruptions.
Maranci argues that these uncertainties are already changing how global scholars evaluate the US. “You can’t compete for talent in an environment like that,” he says. “Why would anyone want that kind of instability?”
The impacts on US science
Immigration challenges are not new for international scientists in the US. But the scope and frequency of the challenges have changed, as well as the sheer scale of the country’s dependence on foreign-born talent to sustain its research enterprise.
According to National Science Foundation data, foreign-born workers now make up 22% of the overall US STEM workforce—but their presence is far more pronounced at the highest levels of scientific training and discovery, where, in 2024, they accounted for roughly 43% of doctorate-level professionals in science and engineering occupations.
These trends mirror what is happening at the training level. Shulamit Kahn, an economist at Boston University, notes that in key STEM fields, international students earn a majority of US PhDs—56% in areas like computer science and engineering—leaving US firms heavily reliant on talent from abroad. The stakes are high for chemistry specifically, Guerra notes, where 64% of postdocs in top chemistry programs hold temporary visas.
Many of these researchers remain in the US after training, Kahn says, and move directly into research-intensive roles, often in industry. More than half work outside academia, with about two-thirds engaged in research, and the longer they stay, the more likely they are to move into supervisory positions that prepare the next generation of researchers and innovators.
This reliance on immigrant talent is directly reflected in US innovation output as well. Guerra notes that immigrants are directly or indirectly responsible for an estimated 36% of US patent output.
“The loss of an immigrant inventor produces measurable declines in native-born collaborator productivity,” he says, meaning that when these scientists leave, the output of their US-born colleagues falls as well. “A sustained diversion of this talent would weaken not just the foreign-born research workforce but the domestic one as well.”
That risk is no longer theoretical.
This dependence could leave US science and innovation vulnerable, as the international researchers who now make up much of the research workforce remain insecure amid tightening policies and increasingly unpredictable visa processes, says Majumdar.
Kimbis and Guerra both note that migration away from the US is accelerating, with competitors such as the UK, the European Union, China, and India ramping up their recruiting to capitalize on US retrenchment. Guerra says, however, that while the early signs of researchers changing their plans is real, it is too soon to call it a mass exodus.
But even these early movements may be hard to reverse. As Aw notes, even if US policies reversed tomorrow, “it would take over a year of consistency to rebuild even a modicum of global trust.”
The current administration, however, maintains that its policies are necessary for national security.
In a statement offered on condition of anonymity, a Department of State spokesperson says the administration is “upholding the highest standards of national security and public safety,” emphasizing that “entry to the United States is a privilege—not a right—and that the safety of the American people comes first.” The department maintains it continues to issue visas to “legitimate researchers” who do not pose a security risk.
But even for international researchers in the US who are not facing immigration-related challenges, current policies are impacting their decision-making. Kumar and Mohammad, who have personally contributed to US research output and innovation, say they would leave the US if they did not have obligations tying them there.
“Scientific dominance is a reputational asset that is easy to destroy and nearly impossible to regain.”
Shulamit Kahn, economist, Boston University
For Kahn, these isolated ripples are propagating throughout the nation.
“I personally know of students who were accepted to graduate programs in the US becoming no-shows,” Kahn says. “I personally know of students who chose to leave the US after graduating because of the recent hostile environment and having great opportunities outside the US. I personally know [international] faculty in the US who are looking around to what other countries might be able to fund their research or where there is more academic freedom.”
As she suggests, “Scientific dominance is a reputational asset that is easy to destroy and nearly impossible to regain.”
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