NOW Supplements, NAC (N-Acetyl Cysteine) 600 mg with Selenium 100 Capsules Review

NOW NAC 600 mg with Selenium is offered as capsules, listed on this page at 250 capsules per bottle, with a 100 capsule size also available in the size selector. The product is presented under the headline benefits of free radical protection, the inclusion of selenium, and support for maintaining cellular health. The page explains that N-Acetyl Cysteine (NAC) is a stable form of the non-essential amino acid L-Cysteine. It is described as a sulfur-containing amino acid that acts as a stabilizer for the formation of protein structures and is also necessary for the formation of glutathione. Selenium is described as an essential trace mineral that facilitates the production of several important enzymes. The Supplement Facts panel lists a serving size of 1 capsule with 250 servings per container. Each serving provides 600 mg of N-Acetyl Cysteine (NAC), with no established Daily Value. The selenium content is listed as elemental selenium from 5 mg of L-Selenomethionine, providing 25 mcg per serving, which the page shows as 45% of the Daily Value. The suggested use is to take 1 capsule twice daily. The page carries a warning that the product is for adults only and advises consulting a physician if pregnant or nursing, taking medication, or having a medical condition. Other ingredients are hypromellose in a cellulose capsule, vegetable source stearic acid, citric acid and microcrystalline cellulose. The page states that the product is not manufactured with wheat, gluten, soy, milk, egg, fish, shellfish, tree nut or sesame ingredients, and that it is produced in a GMP facility that processes other ingredients containing these allergens. Storage instructions say to keep the freshness packets in the bottle until it is empty, keep the bottle tightly closed between uses, and store it in a cool, dry place after opening. The page states that the product is made and quality tested in the USA with globally sourced ingredients. The bottle is made from 100% post-consumer recycled resin. The page notes that natural color variation may occur when the product is exposed to air and that speckling in the capsule may occur without affecting product quality. Listed badges include Kosher, Non-GMO, Halal, and Dairy Free, along with a 100% Money-Back Guarantee. The page offers a one-time purchase at $29.99 or subscription delivery options ranging from every 30 days to every 120 days, with subscription orders over $35 shipping free. The listed price works out to $0.12 per serving. The page also carries the statement that these statements have not been evaluated by the Food and Drug Administration and that the product is not intended to diagnose, treat, cure, or prevent any disease.

Product Focus: Lungs and BreathingAlso covers:Immune system
Tier ⓘ
Members see this product's tier and why. Tiers run from 1, the strongest evidence, to 5. How we grade →
Evidence ⓘ
How strongly the evidence says this product works: human studies count most, then real reviews, then our biohacker panel.
Positive Reviews
Biohacker Mentions
Cost per month
$7

Study, Trial or Testing Result Summary

MembersHuman studies

18 of these 91 human studies gave the ingredient by drip or inhaler, not by mouth.

The main ingredient, N-acetyl cysteine, is taken at a dose of 1,200 mg a day. For long-term lung disease the results are . …

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

Review Totals and Summary

Members48,947 reviews
48,947 reviews · Iherb 46,440 · Vitacost 1,960 · Walmart 344 · Swanson Vitamins 129 · Nowfoods 74

NOW Supplements' NAC (N-Acetyl Cysteine) 600 mg with Selenium 100 Capsules has garnered approximately 129 ratings across various stores, with a of customers, , giving it 4 or 5 stars. Overall, feedback suggests a generally experience for users. **What buyers say it did for them** customers report from taking these capsules. …

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

Biohacker Summary

MembersWhat our biohacker panel says

The main reasons are thyroid , including turning thyroid hormone into its active form and Hashimoto's, along with antioxidant and detox support, glutathione, male fertility, and against mercury. panelists prefer food sources such as Brazil nuts, sardines, seafood, and eggs, and one mentioned a dose of 200 micrograms for fertility. …

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

RAL Summary

MembersThe tier and why

More Details

MembersBody systems · Combine with · Possible side effects

Body systems: Respiratory system, Immune system. Combine with and possible side are for members.

Members see the full analysis, checked against their own meds and goals. Start My 7-Day Free Trial →

Supplement Facts

Selenium 25 mcg · N-Acetyl Cysteine 600 mg
Supplement Facts
Serving Size 1 Capsule
Servings Per Container 100
Amount Per Serving% Daily Value
Selenium (elemental) (from L-Selenomethionine)25 mcg45%
N-Acetyl Cysteine (NAC)600 mg†
† Daily Value not established.

Other ingredients: Hypromellose (cellulose capsule), Stearic Acid (vegetable source), Citric Acid and Microcrystalline Cellulose.

Directions: Take 1 capsule twice daily.

Label source: the brand's label · Report a label change

Where to Buy

Swanson · Pasioonline · Freshthyme
SwansonBuy ↗
PasioonlineBuy ↗
FreshthymeBuy ↗

We sell no supplements. Prices change; check the store.

More lungs and breathing products

MembersThe highest ranked for the same goal

Read more

Our articles on this subject

Graded October 28, 2026 by the Reverse Age Lab evidence engine, from human studies, real reviews and our biohacker panel. How we grade. Is this medical advice? No. Rala organizes the published evidence; go over any change with your doctor, especially if you take meds.