Improvement after a supplement is not the same as a comparative result
Start with the comparison. A before-and-after change alone cannot isolate the contribution of an ingredient.
NAC
Selected research topic
Stress and mood
Some measured outcomes improved in human comparison studies. Read these findings with their populations and conditions.
Some findings concern patients or people with a deficiency.
- Publications for this topic
- 8
- Human comparison publications
- 1
- Publications needing review
- 5
Findings in the studies
bipolar depression
- A better result than the comparison group was reported.Patient group · Single ingredient
Measurement and study conditions
- Study type
- Meta-analysis
- Study population
- Human participants · Patient group
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups. · Study comparison: NAC augmentation versus placebo in bipolar depression; pooled moderate effect with 95% CI 0.06–0.84
- Additional measurement information
- Primary outcome
- Measurement time
- baseline to endpoint; trial durations varied
Oxidative Stress
Other human research, including observational studies and reviews
- A change was reported, but the comparison could not be confirmed.Single ingredient
Measurement and study conditions
- Study type
- Other evidence
- Study population
- Human participants · Participant characteristics were not confirmed.
- Ingredients tested
- Single ingredient
- Measurement time
- Not confirmed.
Depressive symptoms
Research with unclear study subject or type
- The study reported improvement in this measurement.
What the comparison group used was not confirmed.
Single ingredientMeasurement and study conditions
- Study type
- Meta-analysis
- Study population
- Recorded population category: Patient group. Whether the research involved humans needs confirmation.
- Ingredients tested
- Single ingredient
- How results were compared
- Results were compared between groups.
- Measurement time
- Not confirmed.
This result is held for interpretation. That does not mean research found no effect.
Outcome groups needing additional review (1)
- depressive symptoms scores · Distinct papers needing additional review: 1Evidence criteria check: 1
One paper can appear under multiple measured outcomes or review reasons, so these counts should not be added together.
Representative outcome and study details
Partial research summary
Studies with an unspecified organism reported between-group improvement in Depressive symptoms.
These conditions come from related studies and may not describe a single paper.
Single-ingredient studies · Includes patient groups · between-group comparison
2 publications linked to this result (1 awaiting review included)
- Study conditions differ; results are shown descriptively and are not pooled.
- Some publications have not cleared source or interpretation review.
- Some papers could not be reviewed, so this summary covers only findings that could be confirmed.
Data coverage and detailed study classifications
Paper counts are separated by research topic below. One paper may contribute to multiple findings.
Analysis status: Public-ready
Ingredient analysis date:
How the grade was determined: C
The 18.8 evidence score includes 1 independent human studies and 1 clinical studies in the representative benefit area. The C tier remains conservative because of limited repetition across independent human clinical studies, too few clinical findings with an explicit effect direction.
The grade is based mainly on the research area with the most evidence. It does not mean the same result was found in other areas.
Papers linked to this ingredient overall: 109
Papers linked to this topic 8 · distinct papers 8 · papers with a confirmed human comparison 1 · papers needing additional review 5
A publication may appear in more than one count. These numbers should not be added. Ingredient-wide papers, topic-linked papers, and sources in outcome groups use different scopes. Adding source counts may count the same paper more than once.
- bipolar depression: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 1
- Depressive symptoms: Sources represented in this measurement group: 2 · Distinct papers with human comparisons for this outcome: 0
- depressive symptoms scores: Sources represented in this measurement group: 1 · Distinct papers with human comparisons for this outcome: 0
- Oxidative Stress: Sources represented in this measurement group: 2 · Distinct papers with human comparisons for this outcome: 0
What the research found
bipolar depression
The study reported improvement in this measurement.
Meta-analysis · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Depressive symptoms
The study reported improvement in this measurement.
Meta-analysis · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Oxidative stress
A change was reported, but the comparison could not be confirmed.
Other evidence · Single ingredient · Unspecified population
Analysis coverage and paper counts
1 paper · 1 measured outcome
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
depressive symptoms
The study needs further checking before its result can be interpreted.
Meta-analysis · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
depressive symptoms scores
The study needs further checking before its result can be interpreted.
Meta-analysis · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Oxidative Stress
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Patient group
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Controlled study in people · Single ingredient · Patient group
Between-group comparison
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
Unspecified measured outcome
The study needs further checking before its result can be interpreted.
Review · Single ingredient · Unspecified population
The comparison could not be confirmed.
Analysis coverage and paper counts
1 paper · 1 measured outcome
1 papers held from direction counts
Review overlap with primary papers is unknown; counts stay separate.
Direction counts are distinct papers within each row. Outcome contributions count endpoint results, so one paper may contribute more than once.
How to read research findings
How should I read research findings?
Research guidesNo clear difference and an uninterpretable result are different
A reported null comparison contains a result. An abstract without an interpretable comparison leaves a question unresolved.
Paper counts and study counts are different
Count original research separately from research that reanalyzes it. Publication volume is neither replication nor a quality rating.
Side effects and combination findings
Findings from this ingredient alone are shown separately from those involving another supplement or medication.
No reviewed caution rules are available yet. Reported caution findings are shown below.
Review 1 combination findings and 0 findings that outperformed an ingredient alone.
Findings to review with care
Side effects reported for the ingredient alone are separated from findings involving another supplement or medication.
Side effects reported with this ingredient alone
Symptoms or adverse events reported in studies without another active ingredient.
Side effects1 papers
No relevant side effects were observed after NAC administration.Human studies · Study type not identifiedGastrointestinal adverse events1 papers
N-acetylcysteine has an optimal tolerability profile, with gastrointestinal events being the most frequently reported adverse events.Human studies · Systematic reviewAdverse Events1 papers
Common adverse events of NAC include anaphylactic, cutaneous, and intestinal reactions, especially with intravenous administration.Human studies · Systematic reviewReported improvements with combinations
Combination findings are grouped by how the study compared them. This is not a recommendation to combine ingredients.
Combinations with reported improvement
The combination showed improvement, but each ingredient's contribution is unclear.
GlycineIn a randomized clinical trial of older adults, GlyNAC (a combination of glycine and NAC) supplementation for 16 weeks improved glutathione deficiency, oxidative stress, and mitochondrial dysfunction compared to placebo.