I’ve tested more than 200 serums, and somehow, the $5 bottle sitting on my bathroom shelf is the one I keep reaching for.

Good Molecules has become my go-to drugstore skincare brand, and this serum is a big reason why. The formula is simple: it uses hyaluronic acid to help draw moisture into the skin, along with glycerin and propanediol. It’s also fragrance-free, vegan and cruelty-free.

The first thing I noticed about its Hyaluronic Acid Serum was the texture. It’s lightweight, spreads easily and doesn’t leave my skin feeling covered in a thick layer of product. After applying it, my skin feels softer and more hydrated without the sticky finish I’ve experienced with some other hyaluronic acid serums.

That matters because I don’t want a hydration step that fights with everything else in my routine. I want to put it on, let it absorb, add moisturizer and move on. Good Molecules makes that easy.

The price is another reason this bottle stands out. I’ve tried luxury serums that cost dramatically more, and I don’t see enough of a difference in everyday hydration to justify spending that much. Drunk Elephant’s C-Firma Fresh Day Serum, for example, costs $79, while Good Molecules is only $5.

Not to mention, it’s one of the best early Prime Day beauty deals I found before Amazon’s event kicks off on Oct. 6.

I also prefer Good Molecules when I want a straightforward hydration serum. Unlike Drunk Elephant’s orange-toned vitamin C serum, Good Molecules’ hyaluronic acid serum focuses on hydration without leaving that kind of colored residue on the skin.

After testing more than 200 serums, I’ve learned that a higher price tag doesn’t automatically mean better skin. Good Molecules leaves my skin feeling plump, soft and genuinely hydrated without making it feel greasy or weighed down. I notice the difference most when I use it consistently: my skin feels smoother, looks fresher and has that comfortable, moisturized feeling I’m always chasing from a serum.

At this point, I’d happily reach for this $5 bottle over spending $79 or $160 on a luxury serum just for the name on the packaging. I like knowing I can get the hydration my skin needs without overcomplicating my routine or emptying my wallet. Trust me, it’s the bottle that won’t move off your bathroom counter.

What are the ingredients in this serum?

It contains water, propanediol, glycerin, 1% sodium hyaluronate, hydroxyacetophenone, sodium citrate, citric acid and ethylhexylglycerin.

How often should I use this hyaluronic acid serum?

You can use it twice daily, both morning and night, after cleansing and before moisturizing.

Why should this serum be applied to damp skin?

Hyaluronic acid is a humectant that binds to water, so applying it to damp skin maximizes hydration and prevents dryness.

Why is this Good Molecules serum so popular?

It’s highly popular for its extreme affordability, ingredient percentage transparency and gentle, fragrance-free formula.

Is this serum effective for dry skin?

Yes, it deeply hydrates dry skin, but must be layered under a heavier moisturizer to lock in the moisture.

What is the return policy for this serum?

Direct purchases feature a 60-day satisfaction guarantee, while purchases from external retailers like Amazon are subject to their respective return policies.

Your Prime Big Deal Days FAQs, answered

What is Prime Big Deal Days and when is it?

Prime Big Deal Days — fondly known as October Prime Day — is Amazon’s biggest fall sale, offering massive discounts before the holiday rush of Black Friday and Cyber Monday. October Prime Day runs from Tuesday, Oct. 6 to Wednesday, Oct. 7, 2026.

Prime Day vs. Prime Big Deal Days

Prime Day and Prime Big Deal Days are both Prime member-exclusive seasonal sales with massive discounts on rotating bestsellers. Unlike July’s Prime Day, Prime Big Deal Days runs every October as a precursor to the busy holiday season, allowing shoppers to start saving on gift shopping early.

Do you have to be an Amazon Prime member to shop?

October Prime Day is exclusively available to Prime members. However interested shoppers can grab a 30-day free trial to try Prime, and its many benefits with no strings attached, and gain access to exclusive deals and the convenience of fast, free shipping.

What are the best deals?

From reporting on Amazon sales for years, we can tell you for certain that Amazon’s October Prime Day is the ideal time to save on big-ticket tech, Amazon devices, gift-worthy clothing and beauty and skincare staples, household essentials and many more Amazon best-sellers.

Is it worth it?

Every Prime Day sale is a great chance to score deals on thousands of best-sellers, top tech and appliances and every day essentials, but Amazon’s October event also has great pre-holiday discounts on gifts. Our team diligently sorts through all the offers to find the very best items to grab on sale.

When is the next Prime Day?

Already wondering when Amazon’s next Prime Day is? We expect Prime Day to return in summer 2027, but anticipate just-as-good (if not better) deals coming this Black Friday and Cyber Monday. Follow Post Wanted’s around-the-clock coverage, and you’ll be the first to know about headline-worthy sales. Click here to find all of the best deals.

This article was written by Victoria McDonnell, New York Post Commerce Journalist & Content Strategist, who has spent countless hours researching, testing hundreds of products and comparing the latest makeup, skincare, hair and beauty items and trends to determine what’s truly worth your hard-earned cash. She evaluates formulas, textures, ingredients and more, in addition to consulting medical and industry experts. Some of Victoria’s latest conquests include testing the best sheet masks on the market, and a rinse-and-repeat review of the best shampoos for all hair types and budgets. Victoria, who received a beauty industry essentials certification from the Fashion Institute of Technology, has been creating shopping guides for the New York Post since 2021 and previously held positions at Insider Reviews and CNN Underscored.