Since the rollout of 5G smartphones starting around 2019–2020, many people have wondered how SAR values (Specific Absorption Rate) differ from those of 4G LTE phones. Does 5G mean higher radiation absorption? Are the safety limits the same? Let’s break it down based on current science, regulations, and real-world data (as of 2026).
Quick Recap: What is SAR Again?
SAR measures the rate at which radiofrequency (RF) energy from a phone is absorbed by body tissue, in Watts per kilogram (W/kg). It’s tested at maximum power in lab conditions (e.g., phone pressed against a head or body phantom). Limits ensure no harmful heating occurs:
- FCC (USA): 1.6 W/kg averaged over 1 gram of tissue (head/body).
- ICNIRP/EU/most countries (including Pakistan): 2.0 W/kg over 10 grams.
All certified phones — 4G or 5G — must stay below these limits.
Key Differences in 5G vs. 4G SAR
5G introduces two main frequency ranges, which affect how SAR is measured and behaves:
- Sub-6 GHz 5G (FR1 – most common in 2025–2026)
- Frequencies: ~600 MHz to ~6 GHz (overlaps a lot with 4G bands).
- Uses the same SAR measurement as 4G (1g or 10g averaging).
- Typical SAR values for modern 5G phones are very similar to recent 4G phones — often in the 0.5–1.5 W/kg range for head/body.
- Examples from recent models (2024–2025 data):
- Samsung Galaxy S25 series: Head ~1.12 W/kg, Body ~0.73 W/kg (cellular).
- Many flagships (iPhone 15/16 series, Google Pixel, Samsung A/Galaxy lines): Head SAR usually 0.8–1.4 W/kg.
- Low-SAR options still exist (e.g., some older or budget models under 0.5 W/kg, but newer 5G ones trend similar to high-end 4G).
- More dynamic power control (5G adjusts faster/more frequently).
- Higher peak bursts or “crest factors” in transmissions.
- But these stay well below limits, and overall exposure often remains comparable or even lower in good-signal areas because 5G is more efficient.
- mmWave 5G (FR2 – high-band, 24–40+ GHz)
- Used in dense urban areas for ultra-fast speeds (limited coverage globally).
- SAR is not used for compliance above ~6 GHz. Instead, regulators switch to Power Density (PD) limits (e.g., incident power on skin in W/m²).
- Reason: mmWave penetrates only ~1–2 mm into skin (mostly surface heating, no deep tissue like sub-6 GHz or 4G).
- ICNIRP 2020 / FCC updated rules: PD limits ~10–50 W/m² (public/occupational), averaged over small areas (e.g., 4 cm² or 1 cm² at very high frequencies).
- Result: mmWave contributes very little to traditional SAR readings. Phones with mmWave antennas (e.g., some US models) have separate PD compliance, but head/body SAR is driven by sub-6 GHz radios.
Why Do Some People Think 5G Has “Higher SAR”?
- Marketing/antenna design: 5G phones often have more antennas (MIMO) and beamforming, leading to variable power patterns. Some models test higher in worst-case lab scenarios.
- Real-world variability: Studies show 5G uplink (phone transmitting) can fluctuate more intensely than 4G, with occasional higher peaks during heavy data use. But averages and compliance levels remain safe.
- Misinformation: Claims of dramatically higher SAR often ignore that all phones drop power dramatically in real use (strong signal = low power), and 5G networks are designed for efficiency.
Comparison Table: 5G vs 4G SAR Aspects
| Aspect | 4G LTE (Typical) | 5G Sub-6 GHz (Most Use Cases) | 5G mmWave (Limited) |
|---|---|---|---|
| Frequency Range | ~600 MHz – 3.5 GHz | ~600 MHz – 6 GHz | 24–40+ GHz |
| SAR Measurement Used? | Yes (1g/10g) | Yes (same as 4G) | No — Power Density instead |
| Typical Head SAR (2025 models) | 0.5–1.5 W/kg | 0.7–1.4 W/kg | Minimal contribution to SAR |
| Penetration Depth | Deeper (cm into tissue) | Similar to 4G | Skin surface only (~1–2 mm) |
| Real-World Exposure Trend | Baseline | Slightly higher peaks in some apps, but compliant | Very low deep-tissue exposure |
| Regulatory Limit | 1.6/2.0 W/kg | Same | PD: e.g., 10 W/m² public (ICNIRP) |
Bottom Line for Users (Including in Pakistan)
- No major safety difference — 5G phones comply with the same SAR limits as 4G ones for sub-6 GHz (the dominant band). mmWave adds negligible deep-body absorption.
- Overall RF exposure from your phone hasn’t dramatically increased with 5G adoption; networks optimize power better.
- If concerned: Check your phone’s SAR (often in settings > legal/regulatory or manufacturer’s site), prefer low-SAR models, use speaker/earbuds, and keep distance during calls.
- Scientific consensus (WHO, ICNIRP, FCC updates through 2025): No established health risks from compliant phone use, including 5G.
5G brings faster speeds and better efficiency — the SAR story is mostly “evolution, not revolution.” Stay informed, but no need for alarm based on current evidence.