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Renpho is widely known for its affordable massage guns, body measuring tapes and smart scales, many of which have landed in our round-ups of the best health and fitness products we have tested. This company has been a global powerhouse in the wellness industry for nearly a decade now, and has amassed legions of loyal fans worldwide. And now
Renpho has ventured into the highly competitive world of fitness trackers with the release of its first-ever smart ring — the Renpho Lynx.
All that, and it is reasonably priced for a smart ring ($229) and does not require a subscription. On paper, the Renpho Lynx looks like it could make its way into our guide to the best smart rings — but can it live up to our expectations and deliver on performance? We were keen to find out.
Renpho Lynx smart ring review
Renpho Lynx: Design
- Light, but clunky and uncomfortable to wear
- Utilitarian looks may not appeal to everyone
- Durable and difficult to scratch
Key specs
Weight: 0.14-0.17 oz (4-5 g)
Dimensions (in): 0.87 x 0.87 x 0.12
Dimensions (mm): 22 x 22 x 3.04
Colors: Black and silver
Finish: Carbon and titanium
Sizes: Eight (6 – 13)
Battery life: Up to 12 days
GPS: No
Water resistance: 5ATM
Sizing kit: Available
App compatibility: Renpho Health, Apple Health and Google Health Connect
The Renpho Lynx comes in two color options, black carbon and silver titanium, and is available in eight sizes (6 – 13). If you are unsure about the correct fit, you can request a sizing kit before purchase — this costs around $2 to $4 (depending on the retailer), which can then be later deducted from the price of the ring. The range of customization here may not sweep you off your feet, but there are enough options to suit a relatively wide range of potential users.
Our testing unit came in silver titanium, size 12. We have mixed feelings about its design, to say the least.
On the plus side, the Renpho Lynx feels very light yet surprisingly durable. We tested it for about three weeks, exposing it to harsh winter conditions and a range of different workouts, and it has not sustained a single scratch. That’s impressive, given that most smart rings we tested showed signs of wear-and-tear in the first few weeks of testing. The Renpho Lynx is very practical in its design, making it a good pick for those who do contact sports or a lot of manual handling throughout the day.
That’s where the good things end, though.
Most importantly, we did not warm to the rather “masculine” and utilitarian looks of our Renpho Lynx. When it comes to smart rings, style and appearance do matter a lot — they are still a piece of jewellery at the end of the day. Many people wear them when they need something sleeker and more elegant than a chunky fitness watch, and often to complement work attire or formal clothing. The Renpho Lynx, however, looks unappealingly basic and, dare we say, cheap.
We did not find it particularly comfortable to wear, either. Though light, this smart ring felt clunky and unpleasantly uneven on the inside. Even after three weeks of wearing it, we still can’t get used to its presence on our finger. The Renpho Lynx is also relatively thick — it measures around 3.04 mm in width. To put that into perspective, the Oura Ring Gen 4 is approximately 2.88 mm wide, while the width of the Ultrahuman Ring AIR can measure as little as 2.45 mm.
Renpho Lynx: Features
- The app is basic, but it does not require a subscription
- Tracks heart rate, sleep, stress, steps, calories and more
- Comes with a portable charger case
The Renpho Lynx has no display, so as is the case with all screenless wearables, it can only work when it is connected to the app first. Unlike many others, however, it does not require a subscription to do so.
The Renpho Health app is entirely free of charge and is available to both iOS and Android users. This is where you can access all of the stats collected by the smart ring, such as your step count, calories burned, sleep length and quality, heart rate and HRV (heart rate variability), stress levels, SpO2 (blood oxygen) and menstrual cycle predictions.
Each morning, the Renpho Lynx will then use these data points to calculate your Health Index — a daily assessment of your health and fitness status, measured in percentage points. While this sort of a green light/red light system may not be overly scientific, it is simple and easy to understand — not to mention helpful for fitness beginners who may not yet have a good understanding when to push on with intense exercise and when to take a much-needed rest.
That said, we are not big fans of the Renpho Health app. Yes, it feels “clean” and easy to navigate, but it lacks nuance or any genuinely useful lifestyle guidance. We were particularly dismayed by the daily tip section that accompanies your Health Index — it is usually short, overly general and devoid of any practical application (“Good effort! Try to find things that make you feel good”). As such, the Renpho Lynx may not be a good option for fitness beginners or those who require a deep understanding of their health indicators and post-exercise recovery.
It is not all doom and gloom with the Renpho Lynx, though. One feature that scored highly in our books is its portable charger case, which turned out to be an absolute lifesaver for storing and charging the ring on the go. It is compact and portable, but not so small that it’s likely to get lost in the backpack somewhere or fall out of your pocket by accident. We would love to see more smart ring brands follow suit in that regard.
Renpho Lynx: Performance
- 7 to 12 days of battery life
- Inconsistent tracking accuracy
- No major app connectivity issues
According to Renpho, the Lynx comes with approximately 7 to 12 days of battery life, and the charging case can add another seven days on top of that. That claim rings largely true. Our testing unit would last approximately eight to nine days on a single charge, with at least three hour-long training sessions recorded per week. Since real-time workout tracking can be very energy-intensive, it is fair to assume that the Renpho Lynx would probably last much longer without it.
That said, there is no option to add workout logs retrospectively, as is the case with most other smart ring models. The Renpho Lynx also does not have an automatic workout detection. This is a big oversight — the elevated heart rate from exercise can then be easily misconstrued as a sign of stress, and disrupt your overall readings in the process.
Next, the tracking accuracy. This is where the Renpho Lynx suffered a particularly bad blow in our tests. However, this needs to be viewed in the context of how we measured it. Smart rings, the Renpho Lynx included, usually do not produce continuous heart rate measurements in the way fitness watches do. Therefore, it is not fair to validate them using our “go-to” method for testing wrist-worn wearables, which is to wear them alongside a highly precise chest-strap heart rate monitor and then compare the two sets of data.
Instead, we resorted to comparing our Renpho Lynx to the medically-graded Whoop MG band and the premium Oura Ring Gen 4 smart ring. Both of these two screenless fitness trackers have shown us a good degree of accuracy in the past, but again, we can’t vouch for them being correct 100% of the time.
Even so, the discrepancies were just too big to brush off. The Renpho Lynx did produce relatively accurate heart rate measurements during periods of rest or low-intensity, steady-state cardio exercise, true, but anything else would easily throw them off the mark. With High Intensity Interval Training, the heart rate measurements were downright unreliable.
The sleep quality assessments did not impress with their accuracy, either. The Renpho Lynx was generally good at picking up when we fell asleep, but it seemed to have a hard time detecting when we woke up. One time, we were lying awake and motionless in the morning, and that was somehow enough to trick our smart ring into thinking that we were asleep. Not just that, but we were also supposedly in the deep sleep stage. This is not the norm, either — both the Oura Ring Gen 4 and Whoop MG marked that period as us being awake.
Lastly, the Renpho Lynx seemed to have a slight tendency to overestimate our step count and calories burned. In all fairness, though, that seems to be the case with most smart rings.
The app connectivity, on the other hand, works exceptionally well. We have tested enough smart rings to know that they can be very temperamental in that regard, either by disconnecting from the app or struggling to sync the data for no apparent reason. This smart ring, however, did not cause us a single connectivity issue.
True, it took us a good few seconds each morning to establish the app connection, but again, that’s something to be expected from a device this small.
Renpho Lynx: User reviews
At the time of writing this review, both Renpho‘s and Amazon‘s customer reviews placed the Renpho Lynx at a 4.4 out of 5 stars rating. This smart ring tended to be praised for its long battery life, subscription-free app and integration with other Renpho products. Tracking accuracy and size options, on the other hand, received rather mixed feedback, while some users also reported that the battery life is shorter than advertised.
One happy user commented: “I have tried several smart rings, […] but this one from Renpho is the best! I paid about $187, there is no monthly subscription fee, it is very accurate and it connects to the app on my phone with NO ISSUES. I didn’t order the ring sizer. I just ordered the same size as all of the other rings I previously purchased and it was a perfect fit. The absolutely best thing about it is that the battery life lasts 9 – 10 days between recharging.”
Negative reviews tended to mention poor sleep quality assessments and low heart rate tracking accuracy during intense workouts, as well as temperamental app connectivity and issues with Renpho’s customer service.
One disappointed user said: “While it’s comfortable and I love the battery life, it’s useless for tracking activity. It consistently gives me anywhere from about 35% to 50% too many steps. […] Then, the battery seems to be very touch and go, sometimes a day will run you 7-8% and some other days it will run 15% no idea why. If the battery is below 30% exercise mode cannot be run at all. I understand it is a measure to protect the battery/device, but it really makes no sense to me to limit functionality at such a high threshold.”
Should you buy the Renpho Lynx smart ring?
The Renpho Lynx does not live up to its promise. It has some strong points, such as its relatively long battery life, durable and lightweight build, and a subscription-free app. However, it comes with too many performance hiccups and design shortcomings to fully justify its price — unless you really need something tough and long-lasting. But if you prioritize tracking accuracy and in-depth personalized health insights, the Renpho Lynx may not be the best option.
✅ Buy it if: You want a utilitarian, durable smart ring that provides basic fitness stats.
❌ Do not buy it if: You are a fitness beginner looking for your first smart ring, or a serious exerciser looking for complex deep dives into their sleep patterns and post-exercise recovery.
If the Renpho Lynx smart ring is not for you
The Amazfit Helio is an excellent alternative to the Renpho Lynx. It offers similar build quality and a comparable set of tracking features, but it comes with more personalized health insights and notably better tracking accuracy. Not to mention, it costs just $199 and is frequently on sale for as little as $109. However, it also comes with far fewer size and color options.
If you have access, consider the Ultrahuman Ring AIR. While it is currently banned from being sold or imported into the United States due to a patent infringement ruling by the U.S. International Trade Commission (in favor of rival Oura), this neat smart ring is still available in the U.K., E.U. and Australia, second-hand or from third-party sellers. It is subscription-free, stylish, ultra-comfortable to wear and jam-packed with useful features.
Looking for something more premium (and do not mind spending over $349)? Then you can’t go wrong with the Oura Ring Gen 4. It has been our “go-to” smart ring for the past year or so, and for a good reason. It is exceptionally accurate and well-designed, and it continually impresses us with its durable build and genuinely useful assessments of sleep and post-exercise recovery. The biggest downfall? The Oura Ring Gen 4 requires a monthly subscription.
Renpho Lynx: How we tested
We spent two weeks testing the Renpho Lynx, assessing its design, battery life, features, ease of use, app connectivity and value for money. We wore this smart ring during the day, while sleeping and when hiking, rowing indoors or performing low-intensity strength workouts. We also checked online user reviews for any mentions of potential performance issues.
Finally, we assessed the tracking accuracy of our Renpho Lynx by comparing its steps, sleep and heart rate measurements with the data we obtained using two relatively precise screenless fitness trackers: the Whoop MG band and the Oura Ring Gen 4 smart ring.