NEW YORK: For Allison Vecchio, 42, GLP-1 drugs were "a reset button on life," but at a price - side effects like gastrointestinal distress, brittle nails, and feelings of weakness so intense that at times she could not leave her bed.
But the Fort Pierce, Florida-based ER nurse said the symptoms eased when she began a cocktail of supplements that included fiber, collagen and electrolytes, a haul that costs $200 to $300 a month. "You really have to take the reins" to turn mere weight loss into improved health, she said.
GLP-1 drugs like Novo Nordisk's Ozempic and Wegovy rank among the biggest medical breakthroughs in years, owing to their efficacy in treating obesity and type 2 diabetes, and reducing the risk of heart disease. Some 10 million Americans used them last year, a figure that could grow to 25 million by 2030, according to JPMorgan research.
Their side effects, though, have caused many to turn to loosely regulated dietary supplements.
US supplement sales have surged in recent years, surpassing $74 billion in 2025, according to the Nutrition Business Journal. While users swear by them, their growing popularity - fueled in part by social media - has doctors raising red flags and regulators considering new rules around how these products come to market.
Vitamins and supplements don't need preapproval by the US Food and Drug Administration, making their scientific credibility hard to gauge. With social media personalities playing a growing role in their promotion, some medical researchers have called for more regulation of online supplement marketing.
Rob Fried, CEO of Niagen Bioscience, which had $129 million in sales last year, cautioned that companies "can hire an influencer, or even hundreds of influencers on TikTok ... to make whatever claims will sell."
Sales of supplements soar
Vecchio has 25,000 TikTok followers and is on retainer with three brands. She is also a member of TikTok Shop's HealthPro creator program, which is reserved for licensed health professionals.
Pittsburg, Kansas, resident Terri Hart, 52 - a TikToker with more than 12,000 followers - mostly works on commission, perusing products the brands make available to influencers, and promoting the ones she feels helped her the most.
Hart takes magnesium, electrolytes, B12 and other supplements, which she says have helped offset what she called "horrible" nausea, fatigue and constipation after beginning GLP-1s in 2023. They run about $110 a month, costs insurance doesn't cover. TikTok income eases the burden, Hart says.
She says she makes clear she isn't a medical professional, and urges followers to talk to doctors before taking her advice. "I establish my authority through my lived experience," Hart said.
TikTok Shop generated more than $1 billion in dietary supplement sales in 2025, or 5.4% of all e-commerce supplement sales, according to the Nutrition Business Journal, while overall US vitamin and supplement sales grew 5% in 2024 and 7% last year.
The drugs are "bringing in new consumers and expanding existing supplement routines," said Erika Craft, a data analyst at Nutrition Business Journal.
But absent FDA preapproval, people don't know exactly what is in many supplements, said Jonathan Bonnet, a clinical associate professor at Stanford and chief medical officer at the Ardmore Institute of Health in Ardmore, Oklahoma.
"If you can't know what you're taking, it's hard to know what risks you're undergoing," he said.
Retailers offer more supplements
Nearly half of GLP-1 users started taking new vitamins and supplements after beginning the drugs, according to a Nutrition Business Journal survey, with probiotics, protein and fiber particularly popular.
A consumer survey by Boston Consulting Group this year said GLP-1 users spend roughly 20% more on protein, fiber and collagen, a protein that helps maintain skin structure, than before starting the drugs.
Companies are capitalizing. Target is widening its supplement offerings, while private equity-owned The Vitamin Shoppe has seen double-digit sales growth this year in fiber and creatine, which are both popular with GLP-1 users, said Jack Gayton, senior vice president of merchandising at The Vitamin Shoppe.
Mergers and acquisitions in the space are getting bigger, though with fewer transactions. In 2024, there were 115 deals globally worth $7.3 billion, according to financial data firm PitchBook. In 2025, there were 95 deals worth $16.9 billion. Through October 6 of this year, there have been 68 deals worth $14.6 billion.
Procter & Gamble is set to acquire supplement maker Thorne, while Japan's Kirin Holdings announced in August it will buy Canada's Jamieson Wellness, whose US-based brand youtheory released a product aimed at GLP-1 users in early 2025.
Jamieson spokesperson Ruth Winker said the company sees GLP-1s as a tailwind for growth beyond combating side effects. "As people get healthier, they tend to take more vitamins and supplements," Winker said.
Regulations in the offing
US Health and Human Services Secretary Robert F. Kennedy Jr. has proposed tighter regulations. The FDA this year has stepped up efforts to strengthen oversight of new dietary ingredients, issuing new guidance on what submissions for review should include.
Many supplement makers avoid this review process by using a pathway that allows food companies to declare ingredients "generally recognized as safe" without notifying the FDA. But a proposed rule would eliminate that option as part of Kennedy's broader effort to regulate food ingredients.
The proposal has divided the industry. Some support more regulation, lamenting unscrupulous actors who spike supplements with drugs or add only tiny amounts of touted beneficial ingredients.
"At a minimum, a review process should happen prior to launch," says Jacqueline Maslan, CEO of Body of Work, a vitamin startup aimed at women under 40.
But supplement trade group the Council for Responsible Nutrition says the rule would cause months of backlogs as the FDA reviews thousands of ingredients.
Thorne CEO Colin Watts said it's "improbable” the FDA could have the manpower to review new ingredients "at the speed needed to keep up with innovation."
In a statement to Reuters, an HHS spokesperson said the FDA is mulling opportunities "to modernize its regulatory approach to keep pace with an evolving marketplace," adding the agency wants to ensure product safety "while supporting consumer choice."