Skin PigmentationPhase 4NCT04875715
Prospective Evaluation of Topical Almond Oil vs Hydroquinone
A Phase 4 study testing Almond Oil and Hydroquinone Topical in people with Skin Pigmentation, run by University of California, Davis at 1 site in United States.
Trial summary
The purpose of this study is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone. Read more about this study
- Who is it for?
- Ages 18 years and older, women only
- Conditions the study is for
- Skin Pigmentation
- What is being tested?
- Almond Oil and Hydroquinone Topical
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 50 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Jul 2021to 1 Dec 2026
- Phase
- Phase 4
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- Women only
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Premenopausal women of Fitzpatrick skin types 3 to 6
Who cannot join
- Those with a nut allergy
- Smoking is an independent risk factor and serves as a confounder for the development of facial aging [18]. Therefore current smokers, those that have smoked within the past year, and former smokers with greater than a 20 pack year history of smoking will be excluded.
- Those with an autoimmune photosensitive condition or a known genetic condition with a deficiency in collagen production (such as Ehlers-Danlos syndrome) will be excluded as this can be a confounder for facial photoaging.
- Hormonal medications or therapies will not be allowed unless they have been stable on their medications for at least 2 months. Examples include oral contraceptives, progesterone-based injections, and estrogen based hormonal replacement therapy.
- Those who have undergone any cosmetic procedures to the face in the 4 months prior to enrollment in the opinion of the investigator. People that have undergone deeper chemical peels (TCA based peels) within 1 year prior to enrollment will also not be eligible.
- Individuals who are unwilling to discontinue vitamin E containing supplements and food sources during the washout and intervention.
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- Individual who are unwilling to discontinue topical cosmetic products during the duration of the study.
- Individuals who are not willing to engage in a two-week washout on topical treatments known to affect facial pigmentation and these agents will be restricted during the study period as well. These include topicals that contain:
- Retinoids such as tretinoin, adapalene, retinol.
- Antioxidant ingredients such as vitamin C or vitamin E.
- Pigment-reducing agents such as hydroquinone, azelaic acid, kojic acid per the discretion of the investigator except for the hydroquinone that is provided in this study.
- Topicals that contain a nut oil or nut extract as part of their ingredient list.
- Furthermore, subjects will be asked to refrain from use of any other topical products for one week prior to each visit apart from the study agents supplied from this study.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Alexis Carrington contact
United States1 site, 1 recruiting
- Recruiting
UC Davis Department of Dermatology, Clinical Trials Unit
Sacramento, California, 95816
Iryna Rybak, BS, 916-551-2636, irybak@ucdavis.edu
Alexis Carrington, MD, 916-551-2636, aecarrington@ucdavis.edu
About this study
Official title: Prospective Evaluation of Topical Almond Oil vs Hydroquinone on the Appearance of Facial Pigmentation and the Stability of the Microbiome
The purpose of this study is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.
Read the detailed description
The purpose of this experiment is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.
There will be a total of 50 subjects:
- 25 randomized to receive almond oil nightly
- 25 randomized to receive 2% hydroquinone nightly
Study Timelines:
- The duration of an individual subject's participation will last from the day of the consent/screening (visit 1) until visit 5 where they will have images taken and measurements collected to assess skin pigment, skin hydration, sebum excretion rate.
- The duration of participation is 4 months.
- The estimated time for the investigators to complete primary analysis is 2 years.
- Conditions
- Skin Pigmentation
- Being tested
- Almond Oil, Hydroquinone Topical
- Medical subject headings
- Pigmentation Disorders
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Almond OilOther
Almond oil
Hydroquinone TopicalDrug
Also called Hydroquinone
Hydroquinone 2% cream
| Study group | Role | What they receive |
|---|---|---|
| Almond oil | Experimental | Almond Oil Pressed Cold Receives: Other: Almond Oil |
| Hydroquinone | Active comparator | Hydroquinone 2% cream Receives: Drug: Hydroquinone Topical |
What is being measured
The primary outcome is the main question the study is designed to answer.
Intensity of facial pigment
Facial images will be obtained and analyzed with the BTBP image analysis system
Measured: 16 weeks
Secondary outcomes (5)
Shifts in the microbiome diversity (Shannon index as an example)
The skin microbiome will be analyzed to assess any changes after topical almond oil application, compared to the use of topical hydroquinone.
Measured: 16 weeks
Quantification for the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia
The skin microbiome will be analyzed to assess the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia
Measured: 16 weeks
Appearance of facial redness
The research team will quantify the presence of facial redness with a SkinColorCatch from Delfin Technologies. This will measure the RGB colors and average them from each participant for each of the visits.
Skin pigment, including the presence of redness, will be measured using a SkinColorCatch from Delfin Technologies. This device shows the RGB Colors, CIE L*a*b* and L*c*h* color space coordinates when the device is applied to the skin.Included is the link to the device (http://www.truesystem.co.kr/product/pdf/SkinColorCatch%20Brochure%202016.pdf).
Measured: 16 weeks
Subjective tolerability assessment
A questionnaire that assesses for stinging, itching, and burning will be utilized.
Measured: 16 weeks
Intensity of facial pigment
Facial images will be obtained and analyzed with the BTBP image analysis system
Measured: 8 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted6 May 2021
- Study start1 Jul 2021
- Primary completion1 Dec 2026 (estimated)
- Study completion1 Dec 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Skin PigmentationStudies of the same condition, open and under way.
- More trials run by University of California, DavisThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 4
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Enrolment
- 50 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, Davis
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Raja Sivamani, MD MS AP, Principal investigator, UC Davis Dermatology
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT04875715
- Sponsor's protocol ID
- 1666478
- Status last verified
- Sep 2026
- First submitted
- 5 Mar 2021
- Last updated
- 14 Sep 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 14 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Prospective Evaluation of Topical Almond Oil vs Hydroquinone on the Appearance of Facial Pigmentation and the Stability of the Microbiome
- ClinicalTrials.gov ID
- NCT04875715
- Acronym / sponsor ID
- 1666478
- Conditions
- Skin Pigmentation
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 50 participants (estimated)
- Lead sponsor
- University of California, DavisUniversity, hospital or other
- Study start
- 1 Jul 2021 (actual)
- Primary completion
- 1 Dec 2026 (estimated)
- Study completion
- 1 Dec 2026 (estimated)
- First posted
- 6 May 2021 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The purpose of this study is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.
Detailed description
The purpose of this experiment is to analyze facial pigmentation and skin microbiome changes after topical almond oil application, compared to the use of topical hydroquinone.
There will be a total of 50 subjects:
- 25 randomized to receive almond oil nightly
- 25 randomized to receive 2% hydroquinone nightly
Study Timelines:
- The duration of an individual subject's participation will last from the day of the consent/screening (visit 1) until visit 5 where they will have images taken and measurements collected to assess skin pigment, skin hydration, sebum excretion rate.
- The duration of participation is 4 months.
- The estimated time for the investigators to complete primary analysis is 2 years.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Almond oil | Experimental | Other: Almond OilAlmond Oil Pressed Cold |
| Hydroquinone | Active comparator | Drug: Hydroquinone TopicalHydroquinone 2% cream |
Who may qualify
- Ages
- 18 years and older
- Sex
- Female only
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (1 listed)
- Premenopausal women of Fitzpatrick skin types 3 to 6
Key exclusion criteria (13 listed)
- Those with a nut allergy
- Smoking is an independent risk factor and serves as a confounder for the development of facial aging [18]. Therefore current smokers, those that have smoked within the past year, and former smokers with greater than a 20 pack year history of smoking will be excluded.
- Those with an autoimmune photosensitive condition or a known genetic condition with a deficiency in collagen production (such as Ehlers-Danlos syndrome) will be excluded as this can be a confounder for facial photoaging.
- Hormonal medications or therapies will not be allowed unless they have been stable on their medications for at least 2 months. Examples include oral contraceptives, progesterone-based injections, and estrogen based hormonal replacement therapy.
- Those who have undergone any cosmetic procedures to the face in the 4 months prior to enrollment in the opinion of the investigator. People that have undergone deeper chemical peels (TCA based peels) within 1 year prior to enrollment will also not be eligible.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Almond OilAlmond oil | Other | Almond oil |
| Hydroquinone TopicalAlso: HydroquinoneHydroquinone 2% cream | Drug | Hydroquinone |
Primary outcome
Intensity of facial pigment
Time frame: 16 weeks
Facial images will be obtained and analyzed with the BTBP image analysis system
5 secondary outcomes
Shifts in the microbiome diversity (Shannon index as an example)
Time frame: 16 weeks
Quantification for the presence of species within the genus Cutibacteria, Staphyloccoccus, and Ralstonia
Time frame: 16 weeks
Appearance of facial redness
Time frame: 16 weeks
Subjective tolerability assessment
Time frame: 16 weeks
Intensity of facial pigment
Time frame: 8 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 14 Sep 2026.
- Learn more or sign up for the study here!Link provided by the sponsor.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Alexis Carrington contact
Raja Sivamani, MD MS AP principal investigator
UC Davis Dermatology
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing Almond Oil and Hydroquinone Topical in people with Skin Pigmentation, run by University of California, Davis at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 13 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 14 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Iryna Rybak (916-551-2636, irybak@ucdavis.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Intensity of facial pigment (time frame: 16 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 14 Sep 2026.