The best Prime Day supplement deals, according to a registered dietitian

Like melatonin, magnesium works as a sleep aid and can also support muscle recovery. We had a registered dietitian test 11 popular magnesium supplements, and this option from Pure Encapsulations came out on top. 

Perhaps one of the best supplement deals of Prime Day, Orgain Collagen Peptides made our list as the best overall collagen powder and is currently more than 50% off. This no-nonsense powder contains just one ingredient: collagen peptides sourced from grass-fed, pasture-raised cattle. 

Each scoop delivers 20 grams of combined type I and III collagen peptides, which may support joint and skin health. Plus, unlike many collagen powders, it's virtually tasteless and dissolves effortlessly into both hot and cold liquids. 

Emerging research suggests that creatine's benefits extend outside the gym. While it's long been a go-to for those looking to make serious muscle gains, it's been linked with potential benefits for brain, heart, reproductive and mental health.

If you're looking to dip your toe into the world of creatine, this deal on Thorne Creatine — our pick for the best creatine supplement — is a great place to start. The supplement is third-party certified, contains just one ingredient and provides a research-backed dose of creatine monohydrate. Our tester reported the powder mixed seamlessly into beverages and was "completely odorless and tasteless."

For those looking to boost their performance on the field or at the gym, Ghost Legend Pre-Workout Powder is an excellent choice. In addition to 300 mg of caffeine, each scoop includes research-backed ingredients, like L-citrulline, beta-alanine, L-tyrosine and more, earning it our pick as the best pre-workout supplement. 

The powder is available in a variety of punchy flavors, like Bubblicious Strawberry and Sonic Cherry Limeade, and we're happy to report its taste is just as bright as its packaging. 

Our tester — who also happens to be a registered dietitian — raved, "When I tested Legend V4, I was impressed by every aspect of the experience. The flavors were phenomenal (in fact, I consider them the "best tasting" variety as well), with no unpleasant aftertaste or digestive upset — a rarity in pre-workouts. During my session, I felt focused, energized and strong, with an excellent mind-muscle connection that I felt elevated the quality of my lifts. My muscles also felt full and pumped by the end of my routine."

I've used this powder on and off for more than 10 years and highly recommend it for anyone looking for a high-quality protein powder that truly nails the vanilla flavor — trust me, that's no small feat. Ora Organic So Lean & So Clean delivers a complete amino acid profile thanks to its plant-based blend of pea, rice, amaranth and sprouted quinoa protein. It's also free of added sugar, sweetened instead with natural monk fruit. The powder is certified organic and third-party tested for purity and potency, earning it our pick as the best organic protein powder for 2025. 

When combined with oat milk in a shaker bottle, the powder provides a smooth consistency with zero clumps or grittiness. While Vanilla is versatile, the Vanilla Chai's warming spices make it a delicious post-workout treat to sip on its own. 

You don't have to be vegan to benefit from this orange-scented multi. Future Kind Essential for Vegans takes a minimalist approach, delivering three key nutrients commonly lacking in vegan and vegetarian diets — though some meat eaters may fall short too. Each serving of these easy-to-swallow soft gels provides 405 mg of combined EPA and DHA omega-3s from algal oil, plus over 100% of your daily needs for vitamins D and B12. 

Backed by third-party testing, sustainably packaged and cruelty-free, this is a multivitamin you can truly feel good about — which is why it earned a spot in our roundup of the best multivitamins of 2025. And you don't have to just take my word for it — our tester was also impressed: "Vitamins in pill form make me very nauseated but not these soft gels. I also love that the company supports animal sanctuaries and uses eco-friendly packaging. I would like to see more companies doing this."

When it comes to the best gummy multivitamins, SmartyPants reigns supreme. Sure, they contain some added sugar (though sugar-free formulations are available), but these fruit-flavored gummies are ideal for anyone who can't stomach the idea of swallowing pills.

Each six-gummy serving delivers an impressive array of essential nutrients — including DHA and EPA omega-3s, which are rarely found in standard multivitamins. Available in both men's and women's formulations, SmartyPants easily secured its spot in our roundups of the best multivitamins for men and women. 

Good health starts in your gut. While not everyone needs a probiotic, women looking to support vaginal, digestive and immune health may want to grab this Once Daily Women's probiotic from Garden of Life, especially while it's on sale. Each capsule packs 16 different probiotic strains, including L. reuteri and L. fermentum, which may help manage or reduce the recurrence of urinary tract infections (UTIs) and yeast infections.

Our tester, who has tried several women's probiotics, vouches for this one. After several months of regular use, she reported fewer recurring yeast infections. Additional highlights: This probiotic is shelf-stable, NSF-certified gluten-free and third-party tested for purity and potency. It also made our list as one of the best probiotics to buy in 2025.

Tossing and turning at night? While it can't make up for good sleep hygiene, Garden of Life Organics Sleep Well Rest & Refresh was our tester's top pick as the best natural sleep aid: "As someone who has tried everything from counting sheep to mindfulness apps, I can personally attest to the effectiveness of these tablets." 

Formulated to be non-habit-forming, this herbal supplement features valerian root, lemon balm and chamomile, all of which have long been used for their calming properties, though research on their effectiveness is mixed. Still, if you're curious whether these herbs can help calm your mind, this deal offers a good excuse to find out.